Previously, for example, the patent literature 1 proposes a pressure sensor. In this pressure sensor, a sensor unit, which outputs a sensor signal corresponding to a pressure, is installed to a case, and a housing is securely swaged against the case to integrate the case and the housing together. Specifically, in this pressure sensor, an introducing hole for introducing the measurement-subject medium is formed in the housing. The sensor unit is installed to the case such that the sensor unit is directly exposed to the measurement-subject medium, which is introduced through the introducing hole. Furthermore, a threaded portion is formed at an outer peripheral surface of the housing.
Here, it is possible to construct a temperature sensor by forming a resistance thermometer element(s), a resistance value of which changes depending on the temperature, at the sensor unit described above to output a sensor signal, which corresponds to the temperature. In this case, as shown in FIG. 14, the temperature sensor may be installed such that a threaded portion J45, which is formed at the housing J40, is threadably joined to a threaded portion J62 of the installation-subject member J61 that has a passage J60, in which the measurement-subject medium flows. When the measurement-subject medium, which flows in the passage J60, is introduced into the introducing hole J42, the sensor signal, which corresponds to the temperature, is outputted from the sensor unit (not shown).
However, the installation structure of the temperature sensor described above may have the following disadvantage. Specifically, a flow direction of the measurement-subject medium in the passage J60 significantly differs (about 90 degrees in the case of FIG. 14) from an inflow direction of the measurement-subject medium from the passage J60 into the introducing hole J42. Therefore, the measurement-subject medium cannot easily enter the introducing hole J42, so that responsiveness of the sensor unit can be easily deteriorated.